US3703926A

US3703926A - Downhole hydraulic pump and engine improvements

Info

Publication number: US3703926A
Application number: US94905A
Authority: US
Inventors: George K Roeder
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-12-03
Filing date: 1970-12-03
Publication date: 1972-11-28
Anticipated expiration: 1989-11-28

Abstract

A downhole hydraulically actuated pump having an engine piston and a pump piston, with the pistons being arranged with diametrically opposed faces which operate within a common fluid chamber. Multiple pump pistons can be actuated by the engine piston so as to enable simultaneous production to occur from a pluraligy of hydrocarbon producing zones, with the produced fluid flowing to the surface of the earth along separate flow paths.

Description

United States Patent Roeder 1 W Nov. 28, 1972 X4 6 smmm 5/// 3HH W44 aa m $3 0 cRcR mwmm 9999 nnnn 5736 @@%M new 3333 e. m w A s P 3 m M... m S ET B um M Mm DW J Y0 8L HR We E mm H mm m G PM ON w DE h w. m

[22] Filed: Dec. 3, 1970 [21] Appl. No.: 94,905

Primary Examiner-James A. Leppink Attorney-Marcus L. Bates [57] ABSTRACT A downhole hydraulically actuated pump having an [51] Int Cl 1 engine piston and a pump piston, with the pistons being arranged with diametrically opposed faces which operate within a common fluid chamber. Multi- [58] Field of Search ........166/l06, 313, 314; 91/222; 417/358, 400, 403, 404

ple pumppistons can be actuated by the engine piston so as to enable simultaneous production to occur from a pluraligy of hydrocarbon producing zones, with the [5 6] References Cited UNITED STATES PATENTS produced fluid flowing to the surface of the earth along separate flow paths.

Sargent .....4l7/400 2,821,141 1/1958 Sargent......................417/403 10 Claims, 11 Drawing Figures r all alllll'lfllllll v y r rffllllllfflfl/lllll ,lfl v 1 I PATENTEnunvze I972 3,703,926

sum 2 or 2 INVENTOR GEORGE KJZOEDEE MARCUS L.BATES HIS AGENT nllllllllllllnlllil Illl IIIIIIII Ill IIIII III!!! II DOWNHOLE HYDRAULIC PUMP AND ENGINE IMPROVEMENTS BACKGROUND OF THE INVENTION Downhole production pumps which are actuated by hydraulic fluid pressure applied from the surface of the earth are known to those skilled in the art. Pumps of this design are usually complex and require many coacting working parts. Prior art examples of these pumps are to be found in my previously issued U.S. Pat. No. 3,517,741 and U.S. Pat. No. 3,453,963, to which reference is made for further background of this invention. There is often a need for a simplified pump design which is rugged in construction and simple in operation. Also it would be desirable to use a downhole fluid actuated pump in a manner to enable production from several different zones to be produced along separate This invention sets forth a hydraulic actuated downhole production pump assembly for pumping fluid from one or more fluid producing zones to the ground level by the provision of a pump assembly having an engine means and a pump means, with the engine means being reciprocated by power fluid which flows. from a valve means. The valve means is connected to a power fluid source which originates above ground level. The pump has a cylinder disposed within a housing which also encloses the engine cylinder; A portion of the housing forms a common chamber which is always exposed to the power fluid by means of a hollow passageway which leads through the engine piston, a hollow valve control rod, and to the power fluid source. Hence, diametrically opposed faces of the pump piston and engine piston are exposed to the power fluid of the common chamber.

Multiple pump cylinders may be radially spaced apart within the engine and pump housing, with each pump cylinder having the lower extremity thereof connected to a different production zone, and with each pump outlet being connected to a different flow conduit for enabling flow of fluid along specific and separate flow paths to the surface of the earth.

A standing valve assembly together with a packer means precludes fluid from each of the production zones from intermingling with one another.

It is therefore a primary object of the present invention to provide a downhole fluid actuated pump of the free or standing type which has a minimum number of working parts therein.

Another object of the present invehtion is the provision of a downhole pump assembly which has a pump cylinder disposed in fluid communication with an engine cylinder.

A further object of the present invention is the provision of a downhole pump assembly having a single engine connected to a plurality of production pumps, with each pump being connected to produce fluid from a different fluid producing formation.

A still further object of the present invention is the provision of a downhole pump and standing valve assembly which enables simultaneous production of fluid to be realized from a dual completed well.

Another object of the present invention is the provision of a new method of producing wells having multiple production zones.

The above and other objects are attained in accordance with the present invention by the provision of a downhole fluid actuated pump assembly having an engine with a piston thereof being directly connected to a production pump piston and with adjacent piston faces of the pump being in communication with one another, with a face of the engine piston, and with the power fluid source, while the remaining face of the engine piston is alternately exposed to the power fluid source so as to enable the power fluid to reciprocate the piston of the production pump.

These and other objects and advantages of this invention will become readily apparent to those skilled in the art upon reading the following detailed description and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational, part diagrammatical, view of a downhole production pump made in accordance with the present invention;

FIG. 2 is an enlarged, longitudinal, cross-sectional, part diagrammatical view of part of the apparatus seen in FIG. 1;

FIG. 3 is a part diagrammatical, longitudinal, part cross-sectional view of a pump which could be fabricated as seen in FIG. 2;

FIGS. 4 and 5, respectively, are cross-sectional views taken along line 4-4, and 55, respectively, of FIG.

FIG. 6 is a fragmentary, part diagrammatical, longitudinal part cross-sectional view of a downhole pump made in accordance with the present invention with the pump being illustrated as operatively disposed within a borehole;

FIG. 7 is a fragmentary, part cross-sectional, longitudinal view of the pump seen in FIG. 6;

FIG. 8 is a cross-sectional view taken along line 843 of FIG. 7;

FIG. 9 is an enlarged part cross-sectional view of part of the apparatus disclosed in FIG. 6; v

FIG. 10 is a modification of the pump of FIG. 8; and

FIG. 11, is a schematical representation of the flow path used in conjunction with the downhole pump of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Throughout the specification, wherever possible, like or similar numerals will refer to like or similar parts.

In FIG. 1, numeral 8 indicates a casing which is disposed within and forms a part of a borehole. Packer 9 prevents fluid flow thereacross and helps maintain a downhole hydraulically actuated pump assembly 10 properly positioned within the borehole. Power fluid enters the valve section of the pump at 12 while production fluid enters the production pump section at 14. The produced fluid exists at ports 15 where it interrningles with the spent power fluid which exits from ports 16, with the mixed fluids flowing to the surface of the earth and to the tank battery or the like.

The valve section 17 is operatively connected to an engine and pump section which are each preferably disposed within a common housing 18. I

Looking now to the details of FIGS. 2-5, the upper interior portion of the pump assembly is seen to be provided with a power fluid inlet 20 which exits into a counterbore at 21. A hollow valve control rod 22 is axially disposed within the counterbore and of the engine working cylinder 23. Piston chamber 24 reciprocatingly receives engine piston 25 therein with the engine piston having diametrically opposed

bosses

26, 27 for controlling the operation of the valve section and for actuating the production pump piston. Power fluid passageway 28 is seen to be formed within the lower boss with the central longitudinal passageway 29 extending up through the piston and into communication with the before mentioned hollow valve control rod.

Production piston 30 has a lower face 31 and is sealingly and reciprocatingly received within a production cylinder 32 in the usual manner so as to force fluid into and out of fluid chamber 32'. The production barrel has an upstanding wall surface 33 attached to a lower adapter 34 so as to form a common chamber which includes annulus 35. The annulus isin communication with

passageways

28, 29, and the interior of the hollow control rod. The force of the power fluid is always effected at 35 by means of the depending end 36 of the hollow control rod. The rod includes a passageway 37 formed in the terminal end thereof which is in flow communication with the hollow control rod and with the ports 28.

Annulus 39 is cyclicly closed by the action of a valve element 43 as the annular groove 40 of the control rod is reciprocated to an upper position by the engine piston. The inlet check valve 41 is suitably connected from the production pump inlet 14 into chamber 32' while'outlet check valve 42 is connected to the production fluid outlet port from the chamber 32'. The check valves are well known in the art and can take on several different forms.

Valve element 43 reciprocates within its illustrated bore and has a circumferentially extending groove formed thereabout which cooperates with the inside peripheral surface of the bore to form an annulus 44.

The annulus flow connects the exhaust port with port 39 on the upward stroke of the piston. On the downstroke of the power piston the element uncovers port 39 so as to permit power fluid to flow at 45.

Engine piston face 47 is alternately exposed to power fluid which flows from port 39 and to the exhaust port 16. Piston face 48 is diametrically opposed to the pump piston face 49, and each of the piston faces are always in communication with power fluid which is eflected at the end of the control rod.

FIGS. 6-11 disclose the method by which a plurality of production pumps may be connected to a single engine piston, and fluid produced from a plurality of hydrocarbon producing zones, while the produced fluid from eachof the zones flows to the surface of the earth along separate flow paths.

As particularly seen in FIG. 6, a fishing neck 51 along with a conventional hydraulic pump packer means is disposed above seal means 52. A foot 9' is provided with a passageway 53 which communicates with annulus 54. The annulus receives fluid from a production zone through perforations 55. A standing valve assembly 56 has ports 57 formed therein which may be moved into alignment with passageway 53. Stinger'58 is telescopingly received within the standing valve assembly and receives fluid from inlet 59 by means of a suction port 60 which is formed in the terminal end of the stinger. Hence fluid can flow from a lower zone, through perforations 61, and into the stinger. Y

Production fluid from the lower zone exhausts at port 62, flows into annulus 63, through ports 64 which are formed in the seat, and up through production pipe 65 which is located within the casing annulus. Annulus 66 is flow communicated with port 66' and with production tubing 67.

Looking to the details of the pump and stinger assembly of FIG. 7, it is seen that the engine piston is provided with radially spaced apart passageways 128 which are flow connected to the hollow valve control rod. The lower piston face 148 is connected to a plurality of connecting rods 149, each of which is disposed within a pump barrel or cylinder 133', so as to be jointly reciprocated by the piston. Inlet 60 is isolated from inlet 69 by means of they O-ring seal placed at groove 68. Inlet 69 is isolated from outlet 62 by means of packer 70. Outlets 15' and 62 are isolated from one another by means of packer 19'.

As disclosed in FIG. 9, the standing valve assembly has a conical shaped axially aligned passageway 81 which sealingly receives seal means 70 of the pump. Central member 71 of the standing valve assembly is telescopingly received within member 72 so as to communicate or to isolate the various passageways with or from one another: The standing valve assembly engages a seat at 73 while a packer 74 isolates annulus 75 from inlet ports 53. The telescoping member has a lowerniost portion 76 which is biased in an upward direction by means of the illustrated spring. Ports 77 are aligned with ports 78 while annulus 79 is aligned with ports 80. Annulus 81 is isolated from annulus 83 by means of seal 70, with annulus 83 being in communication with

passageway

84 and 64. Passageway 84 communicates with chamber 85.

As seen in FIG. 10, the engine pump can be connected to a multiplicity of difi'erent production pumps, as for example, three. Each of the production pumps may be connected to a different production zone by extending the teachings of FIGS. 1 and 9. As seen in FIG. 10, a pump cylinder 233 has a pump rod 249 disposed therein with power fluid flowing through piston 248 by means of passageways 228.

As seen in the diagrammatical representation of FIG. 11, flow to and from each of the pump pistons may be attained by providing spaced apart

packers

86 and 87 for isolating production zone A from production zones B and C. This enables production fluid from zone A to enter the terminal end of the stinger, production fluid from zone B to flow down the casing annulus and into a port located in the foot; and for production C to flow from above packer 87 and into another isolated portion of the foot.

Spaced apart production ports 90 are isolated from one another by the illustrated spaced apart packers 89. Flow from the production ports flow upwardly at A, B, with the production C also including the spent power fluid.

OPERATION being known to those skilled in the art. With the pump properly positioned within the borehole in the illustrated manner of FIGS. 1-5, production fluid from a fluid producing zone enters at the pump suction or inlet 14 as the piston 30 is reciprocated by the engine. Check valve 41 enables fluid to flow through passageway 50 and into the chamber 32 on each upstroke of the piston, while check valve 42 permits flow of fluid from chamber 32 and through production port on each downstroke of the pump piston.

As the engine reciprocates the piston 30, the diametrically opposed piston faces 48, 49 are continuously exposed to power fluid which flows from 38, 37, 29, 28, and into chamber 35. Hence, piston face 47 must have an area which is of a proper ratio with respect to the piston face 49 so as to provide sufficient force to cause the fluid within chamber 32' to flow to the surface of the ground.

In order to downstroke piston 25, fluid enters at 38, 39, 45, and flows into the upper cylinder chamber by means of port 20, thereby forcing the piston in a downward direction. As the piston reaches its lower extremity of travel, valve element 43 is shifted by the action of groove 40 into its uppermost position, whereupon port 39 is now connected to the spent power fluid outlets by means of annulus 44. This action permits power fluid to flow at 29 into chamber 35 thereby forcing the piston in an upward direction due to the difference in the exposed surface area between

pistons

48 and 49.

In order to simultaneously produce fluid from two different production zones, radially spaced apart passageways 128 are provided in the engine piston 25, and a pump piston and cylinder assembly arranged with the pump end being paced in communication with each of the individual producing zones by the employment of the illustrated seat and valve assembly, the details of which are more particularly set forth in my above referred to US. Pat. No. 3,517,741. Where fluid is being produced from a plurality of fluid producing zones, fluid from the lower zone flows at 59 up through the illustrated annulus into ports 77 and 78 where the fluid then enters the hollow stinger and flows into chamber 132 where the pump piston forces the fluid through the production port 62, into annulus 83, passageway 64, up through the production tubing 65, and then to the surface of the earth.

At the same time, fluid from a fluid producing zone and within casing annulus 8 is flow communicated with port 53, annulus 79, port 80, annulus 81, port 69, with the last port being in fluid communication with another of the production chambers which enables the fluid to be forced through outlet 15' where the fluid then flows into the annulus about the pump, into port 66, and up the production tubing 67 along with the spent power fluid.

When the free pump 118 is desired to be retrieved, power fluid is pumped down production tubing 65 thereby forcing the pump from its seat, whereupon the pump travels to the surface of the earth. At the same time member 71 is forced in an upward direction with respect to member 72, thereby misaligning ports 78 and 80 with their respective ports in order to isolate each of the production zones from one another.

After the pump has been serviced, it can be pumped back downhole where it will again assume the illustrated position of FIG 9.

I claim: 1. A hydraulic actuated downhole production pump assembly for pumping fluid from a fluid producing zone to ground level;

said pump assembly including engine means, pump means, power fluid inlet means, spent power fluid outlet means, production fluid inlet means, and production fluid outlet means;

said engine having a control valve means, a working cylinder, an engine piston reciprocatingly received within said working cylinder and dividing said cylinder into a lower and upper chamber, a hollow valve control rod attached to said engine piston and connected to said valve means for moving said valve means from a first to a second position in response to the position of said engine piston;

said pump means having a pump cylinder, a production piston reciprocatingly received within said pump cylinder and dividing said pump cylinder into a lower and an upper chamber, a connecting rod affixed to said engine piston and to said production piston, pump valve means connecting said production fluid inlet means and said production fluid outlet means to the lower chamber of said pump cylinder to enable production fluid to be forced through said pump means;

means connecting said power fluid inlet means to said hollow valve control rod, means forming a passageway from said hollow valve control rod, through said engine piston, and into the lower chamber of said working cylinder;

said lower chamber of said working cylinder being in communication with said upper chamber of said pump cylinder;

said control valve means, when in the first position,

connects said power fluid to said upper chamber of said working cylinder;

said control valve means, when in the second position, connects said upper chamber of said working cylinder to said spent power fluid outlet means to thereby cause said engine means to reciprocate said pump piston.

2. The downhole production pump assembly of claim 1, and further including a second pump cylinder radially spaced apart from the first recited pump cylinder; a second production piston reciprocatingly received within said second pump cylinder and dividing said second pump cylinder into a lower and upper chamber; a second connecting rod affixed to said engine piston and to said second production piston;

another pump valve means connected to the last recited lower chamber for conducting fluid flow from another production fluid inlet to another production fluid outlet;

the last recited upper chamber being in fluid communication with the upper chamber of the first recited pump cylinder and with the lower chamber of said working cylinder.

3. The improvement of claim 2, and further including means by which the lower chamber of said second pump cylinder is flow connected to another production zone which is spaced apart from the first recited fluid producing zone.

4. The improvement of claim 2, and further including means forming a hollow stinger, said stinger being affixed to and depending from said pump means the interior of said stinger forming the first recited production fluid inlet;

a standing valve assembly including a member,

means by which said member is attached to structure associated with a well bore; a central member telescopingly received within said member, means forming a central bore through said central member for slidably receiving said stinger therein;

means forming spaced apartports in said member, means forming spaced apart ports in said central member, means by which one of each port in said member is aligned with one of said ports in said central member when said central member is in a first position with respect to said member, and misaligned with respect to each other when said central member is in a second position with respect to said member; means forming a flow path which enables fluid to flow from one fluid producing formation, through a pair of alignedports, and into said hollow stinger; means forming a flow path which enables fluid to flow from another fluid producing formation, through another pair of aligned ports, and into the first recited production inlet; whereby, fluid produced from two spaced apart formations can be produced by the pump and caused to flow along separate flow paths.

5. The improvement of claim 4, and further including means forming a flow path from one of said production outlets to the surface of the ground; means forming another flow path from the second recited production outlet to the surface of the ground, whereby:

said pump, when properly seated on said central member, produces fluid from two spaced apart production zones along separate flow paths, and; when said pump is removed from said central member, the central member moves with respect to said member to thereby misalign the pairs of ports in said member and said central member to thereby preclude intermingling fluid from the spaced apart fluid producing zones.

6. A pump assembly for pumping a produced fluid from a production fluid inlet to a production fluid outlet by using a power fluid;

said pump assembly including means forming an engine, a pump, a power fluid inlet, a spent power fluid outlet, a production fluid inlet, and a produced fluid outlet;

said engine having a valve means, a working cylinder,

an engine piston, a hollow valve control rod extending from said piston and to said valve means for controlling the action of said valve means;

said pump including a pump cylinder which is located within a depending marginal portion of said working cylinder, a pump piston reciprocatingly received within said pump cylinder; means interconnecting said engine piston to said pump piston;

check valve mean by which one end of said pump cylinder is connected to said production fluid inlet and to said production fluid outlet to cause production fluid to be pumped when said pump piston is reciprocated by said engine;

said pump cylinder and said working cylinder having adjacent end portions in fluid communication with each other;

means forming a flow path for conducting power fluid from said power fluid inlet, through said hollow valve control rod, through said engine piston,

and into fluid communication with the adjacent end portions of the working cylinder and pump cylinder;

said valve means connecting the power fluid inlet to a cylinder chamber formed by the portion of the working cylinder above said engine piston when said hollow control rod is moved into one position by the engine piston; and, said valve means connecting the spent power fluid outlet to said cylinder chamber of the working cylinder above said engine piston when said hollow controllrod is moved into another position by the engine piston.

. 7. The pump assembly of claim 6, and furtherincluding a second pump cylinder'radially spaced apart from the first recited pump cylinder; a second production piston reciprocatingly received within said second pump cylinder and dividing said second pump cylinder into a lower and upper chamber; a second connecting rod affixed to said engine piston and to said second production piston;

pump valve means connected to the last recited lower chamber for conducting fluid flow from a production fluid inlet to a production fluid outlet;

8. The improvement of claim 7, and further including means by which the lower chamber of said second pump cylinder is flow connected to a production zone which is spaced apart from the first recited fluid producing zone. I

9. The improvement of claim 7 and further including means forming a hollow stinger, stinger being affixed to and depending from said pump assembly, the interior of said stinger forming the recited production fluid inlet;

a standing valve assembly including a member,

means by which said member is attached to structure of a well bore; a central member telescopingly received within said member, means forming a central bore through said central member for slidably receiving said stinger therein;

means forming spaced apart ports in said member, means forming spaced apart ports in said central member, one of each ports in said member being aligned with one of said ports in said central member when said central member is in a first position with respect to said member, and misaligned with respect to each other when in a second position; means forming a flow path which enables fluid to flow from one fluid producing formation, through a pair of aligned ports, and into said hollow stinger; means forming a flow path which enables fluid to flow from another fluid producing formation, through another pair of aligned ports, and into the first recited'production inlet, whereby fluid produced from two spaced apart formations can be produced along separate flow paths.

when said pump is removed from said central member, the central member moves with respect to said member to thereby misalign the pairs of ports in said member and said central member to preclude intermingling fluid from the spaced apart fluid producing zones.

Claims

1. A hydraulic actuated downhole production pump assembly for pumping fluid from a fluid producing zone to ground level; said pump assembly including engine means, pump means, power fluid inlet means, spent power fluid outlet means, production fluid inlet means, and production fluid outlet means; said engine having a control valve means, a working cylinder, an engine piston reciprocatingly received within said working cylinder and dividing said cylinder into a lower and upper chamber, a hollow valve control rod attached to said engine piston and connected to said valve means for moving said valve means from a first to a second position in response to the position of said engine piston; said pump means having a pump cylinder, a production piston reciprocatingly received within said pump cylinder and dividing said pump cylinder into a lower and an upper chamber, a connecting rod affixed to said engine piston and to said production piston, pump valve means connecting said production fluid inlet means and said production fluid outlet means to the lower chamber of said pump cylinder to enable production fluid to be forced through said pump means; means connecting said power fluid inlet means to said hollow valve control rod, means forming a passageway from said hollow valve control rod, through said engine piston, and into the lower chamber of said working cylinder; said lower chamber of said working cylinder being in communication with said upper chamber of said pump cylinder; said control valve means, when in the first position, connects said power fluid to said upper chamber of said working cylinder; said control valve means, when in the second position, connects said upper chamber of said working cylinder to said spent power fluid outlet means to thereby cause said engine means to reciprocate said pump piston.

2. The downhole production pump assembly of claim 1, and further including a second pump cylinder radially spaced apart from the first recited pump cylinder; a second production piston reciprocatingly received within said second pump cylinder and dividing said second pump cylinder into a lower and upper chamber; a second connecting rod affixed to said engine piston and to said second production piston; another pump valve means connected to the last recited lower chamber for conducting fluid flow from another production fluid inlet to another production fluid outlet; the last recited upper chamber being in fluid communication with the upper chamber of the first recited pump cylinder and with the lower chamber of said working cylinder.

4. The improvement of claim 2, and further including means forming a hollow stInger, said stinger being affixed to and depending from said pump means the interior of said stinger forming the first recited production fluid inlet; a standing valve assembly including a member, means by which said member is attached to structure associated with a well bore; a central member telescopingly received within said member, means forming a central bore through said central member for slidably receiving said stinger therein; means forming spaced apart ports in said member, means forming spaced apart ports in said central member, means by which one of each port in said member is aligned with one of said ports in said central member when said central member is in a first position with respect to said member, and misaligned with respect to each other when said central member is in a second position with respect to said member; means forming a flow path which enables fluid to flow from one fluid producing formation, through a pair of aligned ports, and into said hollow stinger; means forming a flow path which enables fluid to flow from another fluid producing formation, through another pair of aligned ports, and into the first recited production inlet; whereby, fluid produced from two spaced apart formations can be produced by the pump and caused to flow along separate flow paths.

5. The improvement of claim 4, and further including means forming a flow path from one of said production outlets to the surface of the ground; means forming another flow path from the second recited production outlet to the surface of the ground, whereby: said pump, when properly seated on said central member, produces fluid from two spaced apart production zones along separate flow paths, and; when said pump is removed from said central member, the central member moves with respect to said member to thereby misalign the pairs of ports in said member and said central member to thereby preclude intermingling fluid from the spaced apart fluid producing zones.

6. A pump assembly for pumping a produced fluid from a production fluid inlet to a production fluid outlet by using a power fluid; said pump assembly including means forming an engine, a pump, a power fluid inlet, a spent power fluid outlet, a production fluid inlet, and a produced fluid outlet; said engine having a valve means, a working cylinder, an engine piston, a hollow valve control rod extending from said piston and to said valve means for controlling the action of said valve means; said pump including a pump cylinder which is located within a depending marginal portion of said working cylinder, a pump piston reciprocatingly received within said pump cylinder; means interconnecting said engine piston to said pump piston; check valve mean by which one end of said pump cylinder is connected to said production fluid inlet and to said production fluid outlet to cause production fluid to be pumped when said pump piston is reciprocated by said engine; said pump cylinder and said working cylinder having adjacent end portions in fluid communication with each other; means forming a flow path for conducting power fluid from said power fluid inlet, through said hollow valve control rod, through said engine piston, and into fluid communication with the adjacent end portions of the working cylinder and pump cylinder; said valve means connecting the power fluid inlet to a cylinder chamber formed by the portion of the working cylinder above said engine piston when said hollow control rod is moved into one position by the engine piston; and, said valve means connecting the spent power fluid outlet to said cylinder chamber of the working cylinder above said engine piston when said hollow control rod is moved into another position by the engine piston.

7. The pump assembly of claim 6, and further including a second pump cylinder radially spaced apart from the first recited pump cylinder; a second production piston reciprocatingly received within said second pump cylinder and dividing said Second pump cylinder into a lower and upper chamber; a second connecting rod affixed to said engine piston and to said second production piston; pump valve means connected to the last recited lower chamber for conducting fluid flow from a production fluid inlet to a production fluid outlet; the last recited upper chamber being in fluid communication with the upper chamber of the first recited pump cylinder and with the lower chamber of said working cylinder.

8. The improvement of claim 7, and further including means by which the lower chamber of said second pump cylinder is flow connected to a production zone which is spaced apart from the first recited fluid producing zone.

9. The improvement of claim 7 and further including means forming a hollow stinger, stinger being affixed to and depending from said pump assembly, the interior of said stinger forming the recited production fluid inlet; a standing valve assembly including a member, means by which said member is attached to structure of a well bore; a central member telescopingly received within said member, means forming a central bore through said central member for slidably receiving said stinger therein; means forming spaced apart ports in said member, means forming spaced apart ports in said central member, one of each ports in said member being aligned with one of said ports in said central member when said central member is in a first position with respect to said member, and misaligned with respect to each other when in a second position; means forming a flow path which enables fluid to flow from one fluid producing formation, through a pair of aligned ports, and into said hollow stinger; means forming a flow path which enables fluid to flow from another fluid producing formation, through another pair of aligned ports, and into the first recited production inlet, whereby fluid produced from two spaced apart formations can be produced along separate flow paths.

10. The improvement of claim 9, and further including means forming a flow path from one of said production outlets to the surface of the ground; means forming another flow path from the second recited production outlet to the surface of the ground, whereby: said pump, when properly seated on said central member, produces fluid from two spaced apart production zones along separate flow paths, and; when said pump is removed from said central member, the central member moves with respect to said member to thereby misalign the pairs of ports in said member and said central member to preclude intermingling fluid from the spaced apart fluid producing zones.